1. Field of the Invention
In a typical sugar mill, the juice is first extracted from the cane, lime is added to raise the pH to above 7, the juice is heated, and then goes to a clarifier in which the precipitates formed by the action of heat and lime are eliminated to as great a degree as possible. The clarified juice then travels to a series of evaporators or a multiple effect evaporator where the juice is concentrated from an entering concentration of about 15 or 16% of sugar to a syrup having a concentration of about 65% sugar. The syrup from the evaporators then proceeds to vacuum pans where further evaporation is accomplished by boiling the syrup under reduced pressure. The syrup is evaporated in the vacuum pans until it becomes a saturated or supersaturated solution of sugar. The syrup is then seeded to initiate crystal growth and when an evaporation pan has become filled with a fairly dense mixture of crystals and syrup known as "massecuite" the contents of the pan, called a "strike" is discharged. The strike is normally cooled with slow mixing in a crystallizer to permit additional extraction of sugar from molasses to crystals as the mass cools. The mass is then centrifuged to separate the sugar crystals from the molasses.
In most sugar factories, the "three boiling" system is empolyed. The first boiling of pure syrup yields what is known as A sugar and A molasses. The A molasses with a "footing" of sugar crystals and some syrup is reboiled to provide a second massecuite which in turn provides what is called a B strike that provides B sugar and B molasses. The operation is again repeated with the B molasses in a footing of sugar crystals and syrup. The strike is called a C strike and the crystallization operation then produces C sugar and C molasses, which is the final "black strap" molasses.
The efficiency of the system is determined by minimizing the amount of the final molasses produced for a given amount of sugar juice, as well as having a minimum sucrose concentration in the black strap molasses. Ordinarily, the A and B sugars are sold, while the C sugar is used for seeding and recirculation in liquid form to the A and/or B pan.
The industry is continuously looking for improvements in providing efficient and economic ways to produce sugar, by speeding up crystallization, by enhancing the A and B sugar yields, and by reducing the impurities in the sugar.
2. Description of the Prior Art
U.S. Pat. No. 3,401,059 teaches the use of sodium sulfosuccinate to enhance the efficiency of sugar crystallization.